1. Field of the Invention
The present invention relates to metal detectors. More specifically, the present invention relates to a hand-held metal detector having a hermetically sealed housing with visual, tactile and audible indicators.
2. Description of the Related Art
Metal detectors have been widely used for hobby, commercial, and security application for many decades. Current metal detectors consist of one or more search coils coupled to a detector circuit, which in turn, is connected to a user interface that reports the detection and presence of metallic objects to the operator. The search coil(s) establishes an electromagnetic field, called a search field, which can effectively penetrate non-metallic materials, such as soil, water and other materials. When the search field is moved into proximity of a metallic object, the search field is disturbed and the detector circuit senses this disturbance. Those skilled in the art are familiar with a number of field establishing and field disturbance detecting techniques, which can be used to estimate the size, location, and the content of the metallic objects in question.
A common application for metal detectors is treasure hunting by hobbyists. Desirable target metallic objects sought by hobbyists are coins, jewelry, artifacts, and other treasure, for example. Given a relatively large search area, such as a public park for example, operators will typically select a ground search metal detector that is effective for sweeping a large area with good search field penetration depth. Good penetration for small objects would be approximately six to twelve inches. A ground search metal detector typically employs a relatively large search coil (perhaps six to twelve inches in diameter) that is sequentially scanned back and forth, about one or two inches above the ground surface. To facilitate the user interface, a stem is usually employed to support the search coil and reach upwardly to a comfortable height for the operator to carry the metal detector while standing and scanning the ground. The stem also supports the detector circuit and user interface at a comfortable position, and may include various handles and arm rests for operator comfort. The detector circuit is generally in a housing and may include various interface components, such as a display, audible transducer, tactile transducer, visual transducer, and interface connectors, such as a headphone jack and power supply interface.
During a treasure hunt using a ground search metal detector, a fortunate hobbyist may receive an alert signal from the metal detector indicating that a metallic object has been located. The next step is to dig into the soil and retrieve the treasure. Thus, treasure hunting with a metal detector is a repetitive task, comprising searching and digging. As a practical matter, it is not necessarily easy to retrieve the metallic object discovered using a ground search metal detector. The operator is faced with the task of digging a six to twelve inch hole that is six to twelve inches deep for each alert that the metal detector provides. This issue has been greatly alleviated through use of a pinpointing metal detector, such as the Garrett Pro-Pointer model that is also the subject of U.S. Pat. Nos. D583,261 and 7,575,065, the contents of which are hereby incorporated by reference. The pinpointing metal detector is a hand-held unit having a handgrip portion and a probe portion that provides a compact search field, and that is particularly suited from locating a metallic object discovered in the larger search areas of a ground search metal detector.
In the process of searching for metallic objects it is common to encounter water, and also to conduct searches under water, such as under lakes, streams, puddles and so forth. Further it is not unusual to encounter water as a hole is dug to retrieve an object. In the case of a ground search metal detector, it is a fairly straightforward approach to make the search coil and stem waterproof, and also advise the user that the detector circuit and housing are to be kept away from water. In the case of a pinpointing metal detector, it is a more challenging design issue. The Garrett Pro-Pointer model actually includes an excavating blade on the detector, which encourages the user to dig and scrape with the metal detector within the search hole. When water is present, the issue of water intrusion into the metal detector housing is inevitable. Thus it can be appreciated that there is a need in the art for an apparatus to improve upon the waterproofing and protection of metal detector circuits and their related transducers and interfaces.